Conductive hydrogels: intelligent dressings for monitoring and healing chronic wounds

Abstract

Conductive hydrogels (CHs) represent a burgeoning class of intelligent wound dressings, providing innovative strategies for chronic wound repair and monitoring. Notably, CHs excel in promoting cell migration and proliferation, exhibit powerful antibacterial and anti-inflammatory properties, and enhance collagen deposition and angiogenesis. These capabilities, combined with real-time monitoring functions, play a pivotal role in accelerating collagen synthesis, angiogenesis and continuous wound surveillance. This review delves into the preparation, mechanisms and applications of CHs in wound management, highlighting their diverse and significant advantages. It emphasizes the effectiveness of CHs in treating various chronic wounds, such as diabetic ulcers, infected wounds, temperature-related injuries and athletic joint wounds. Additionally, it explores the diverse applications of multifunctional intelligent CHs in advanced wound care technologies, encompassing self-powered dressings, electrically-triggered drug delivery, comprehensive diagnostics and therapeutics and scar-free healing. Furthermore, the review highlights the challenges to their broader implementation, explores the future of intelligent wound dressings and discusses the transformative role of CHs in chronic wound management, particularly in the context of the anticipated integration of artificial intelligence (AI). Additionally, this review underscores the challenges hindering the widespread adoption of CHs, delves into the prospects of intelligent wound dressings and elucidates the transformative impact of CHs in managing chronic wounds, especially with the forthcoming integration of AI. This integration promises to facilitate predictive analytics and tailor personalized treatment plans, thereby further refining the healing process and elevating patient satisfaction. Addressing these challenges and harnessing emerging technologies, we postulate, will establish CHs as a cornerstone in revolutionizing chronic wound care, significantly improving patient outcomes.

Keywords: chronic wound; conductive hydrogels; electrical stimulation; intelligent dressing; real-time monitoring.

Graphical abstract

Figure 1.

Overview of CHs types and their applications in wound healing. This figure categorizes CHs based on their composition and conductive properties and maps their specific uses across various wound types.

Figure 2.

Types of electronic CHs: (A) Carbon-based CHs: PDA@CNTs were used as the conductive component, and flexible, biocompatible and electrically conductive all-in-one adhesive hydrogels were produced by crosslinking a mixture of gelatin and acrylamide, which are capable of both detecting human motion and accelerating wound healing through electrical stimulation generated by piezoelectricity. Reprinted from Ref. [39]. Copyright 2023, American Chemical Society; (B) CPs-based CHs are electrically CHs: an electrically conductive poly(2-hydroxyethyl methacrylate) (poly HEMA)/PPy hydrogel was prepared, and the electrically conductive nature of the hydrogel in a weakly alkaline physiological environment was preserved by in situ doping of the PPy, allowing its application in the treatment of chronic diabetic wounds with electrical stimulation. Reprinted from Ref. [35]. Copyright 2023, Elsevier; (C) Metal/metal oxide NPs-based CHs: argentum nanoparticles as a conductive component in a hydrogel prepared by crosslinking sodium alginate oxide and carboxymethyl chitosan and applied to full-thickness cortical defect wounds. Reprinted from Ref. [29]. Copyright 2023, Elsevier.

Figure 3.

Types of ionic CHs: (A) Metal salts-based CHs: a conductive hydrogel for adaptive deep wounding was prepared by dynamic crosslinking of PVA and borax, doped with TA and HLC, using borate ions as the conductive component. Adapted with permission from Ref. [30]. Copyright 2021, Elsevier; and (B) ILs-based CHs: a highly stretchable, self-healing ILs-based CHs adhesive with antibacterial and antioxidant properties, promoting methicillin-resistant Staphylococcus aureus-infected motion wound healing. Reprinted from Ref. [31]. Copyright 2023, Elsevier.

Figure 4.

Transepithelial potentials and EF at the wound site before and after healing.

Figure 5.

The diverse roles played by CHs in the wound-healing process, encompass their functions as defenders against bacterial invasion and facilitators of anti-inflammatory inhibition, porters enabling cell migration and proliferation, architects orchestrating collagen deposition and angiogenesis, and monitors providing real-time monitoring of the healing progress.

Figure 6.

Wound repair by CHs: (A) Promoting cell proliferation and migration: the MXene@CeO₂ nanocomposite multifunctional hydrogel FOM scaffolds. ES has been observed to enhance fibroblast cell mobilization and proliferation within these scaffolds. Reproduced with permission from Ref. [56]. Copyright 2021 © Elsevier; (B) Antibacterial and anti-inflammatory: black phosphorus-based CHs (HA-DA@BP) capable of releasing black phosphorus under mildly acidic conditions were prepared by amidation reaction and Fe³⁺ catechol coordination for synergistic electro-antimicrobial effects and wound healing promotion. Reproduced with permission from Ref. [57]. Copyright 2021 © John Wiley and Sons; (C) Promoting blood vessel growth: xanthan gum and silk fibroin-based burn dressings, demonstrated notable efficacy in stimulating dermal collagen matrix formation and promoting blood vessel growth in a rat model. Reproduced with permission from Ref. [58]. Copyright 2024 © Elsevier and (D) Real-time monitoring: the hydrogel matrix, crafted from a combination of aminobenzene boronic acid-grafted sodium alginate, PVA and hydroxylated graphene via dynamic and supramolecular interactions, offers exceptional properties such as bacterial infection detection through electrical signal variations, making it an ideal dressing for bacterial diagnosis, treatment and wound health management. Reproduced with permission from Ref. [59]. Copyright 2024 © John Wiley and Sons.

Figure 7.

Personalized management of chronic wounds with CHs: (A) diabetic wound healing and monitoring of blood glucose: a highly transparent, adhesive and hemostatic CHs patch was fabricated through the in situ assembly of a poly(acrylamide-acrylate adenine) (P(AM-Aa)) polymer network doped with poly(tannic acid) (PTA)-infused PPy nanofibers, enabling indirect detection of glucose levels on the wound surface. Adapted with permission from Ref. [88]. Copyright 2024 © Royal Society of Chemistry. (B) Infected wound healing and bacterial monitoring: a self-healing QCS/OD hydrogel composed of QCS and OD that is further integrated with PVDF to form enhanced heterogeneous interfacial sensors capable of detecting infected wound gases. Reproduced with permission from Ref. [89]. Copyright 2024 © Elsevier. (C) High/low-temperature injury and healing monitoring in extreme environments: a multifunctional CHs composed of PAAm/PEG/hydrolyzed keratin (HK)/MXene was developed as a high-performance, integrated therapeutic epidermal sensor and its dual functionality was exemplified in a rat model of frostbite. Adapted with permission from Ref. [90]. Copyright 2023 © Elsevier; and (D) Wounds at athletic joints and monitoring of movement: an antimicrobial, conductive and antioxidant hydrogel adhesive with high extensibility and rapid self-healing capabilities, making it suitable for the treatment of infected sports wounds and facilitating real-time wound monitoring through its strain-sensing properties. Reproduced with permission from Ref. [31]. Copyright 2023 © Elsevier.